docs: def expand_node_tpm(tpm):
      """Broadcast a node TPM over the full network.
  
      This is different from broadcasting the TPM of a full system since the last
      dimension (containing the state of the node) contains only the probability
      of *this* node being on, rather than the probabilities for each node.
      """
      uc = np.ones([2 for node in tpm.shape])
      return uc * tpm